Abstract: Modular building, as a highly prefabricated building, has the characteristics of standardization, integration and industrialization, and has been rapidly popularized and applied in hotel, mobile cabin hospital and dormitory and so on. Compared with conventional buildings, modular buildings differ greatly in load transfer path, design method, construction mode and structural system. Based on the structural design of modular buildings, the design strategy of modular buildings and the key ideas of industrial application are expounded from the aspects of modular units, structural system, structural design, characteristics and application of modular buildings. Among them, the connection between internal components of module units, the connection between adjacent modules, and the connection between module units and lateral force resistant systems are the keys to the design of modular building structures. In order to promote the industrialization development of modular building, the vertical bearing system and the lateral force system are separated, so that the vertical bearing component is independent of the number of structural layers, making the stacked box structure easy to achieve the standardization of modular products.